Gilfach Meredydd Dame Elizabeth Phillips Estate

[c4626y]

I am interested in tracing the history of a farm above the village of Brechfa.
On the Ordnance Survey Maps going back to 1901 the property is clearly labelled as Gilfach Meredydd.
On the 1831 Map the property is labelled as Llan Meredidd.
I have yet to get access to the maps between 1831 and 1901.
My first query is concerning the change of name ? .
I know the property was part of an estate sold, by Dame Victoria Gladys Elizabeth Phillips of Picton Castle,widow of Sir Henry Erasmus Edward Phillips Baronet, to the Forestry Commission in 1938
I would like to know more of the history of the estate and the tennants.
I would be most grateful for any help.